library(ezknitr)
library(readr)
There are a few things that come to mind when anyone thinks about Vancouver. They might think about nature, mountains, the ocean, and of course, the insane cost of housing. High housing prices and in turn, land value, have become apart of Vancouver's identity; it is for this reason that I am interested in analyzing external effects that may or may not effect the value of land. One of the possibly more overlooked factors is the correlation of land value and public trees. In this analysis, I will see if there is any significance between land value and trees owned, planted, and maintained by the City of Vancouver on public streets.
Using the property tax report for land values provided by the City of Vancouver, as well as the dataset for street trees in Vancouver, this analysis will test the correlation between land value and various attributes of street trees. These attributes include the size, age, number, and location of the trees. Unless otherwise stated, all of the land values are from the most current tax report from 2016.
Figure 1: Mean Land Value by Neighbourhood in 2016:
The map shown above displays the Mean Land Value by Neighbourhood in the City of Vancouver. You can see that the darker areas represent lower land values, while the lighter areas represent areas of higher land value. These shaded areas are generated by taking the average land value per neighbourhood. We can see that land values generally higher in west Vancouver than they are in East Vancouver. To remove any bias toward neighbourhoods with larger property sizes, in this analysis I will focus on the change in land value over time.
Figure 2: Mean Tree Diameter by Neighbourhood:
Similarly to the map shown above in Figure 1, we can see that there is a definite corrlation between mean land value and the mean trunk diameter by neighbourhood. The high land value as seen in Figure 1 correlates directly to the large tree trunk diameters shown in Figure 2 by neighbourhood, respectively. This correlation suggests that neighbourhoods with larger trees typically have higher land values.
Figure 3: Number of Trees Planted by Neighbourhood since 2015:
The map shown above displays the number of trees planted in Vancouver by neighbourhood since 2015. In contrast to Figure 1: Mean Land Value By Neighbourhood, we can see that there have been many trees planted in East Vancouver and the Dunbar neighbourhood since 2015. To test the correlation that trees have on land value, the next analysis will focus on the mean change in land value by neighbourhood between 2015 and 2016. This will test the correlation between trees planted and a change in land value.
Figure 4: Change in Land Value by Neighbourhood between 2015 and 2016:
The above map displays the mean change in land value between 2015 and 2016. The lighter areas represent the greatest positive change, while the darker areas represent the smallest change. We can see that the greatest increase in land value has been in East Vancouver. It seems as though there might be some correlation between the change in land value (Figure 4) and the number of trees planted (Figure 3).
Figure 5: Linear Model of Change in Land Value by Trees Planted per Neighbourhood:
Above is a linear model of the change in mean land value by neighbourhood with respect to the number of trees planted since 2015. The slope of this model would seem to indicate that there is infact no correlation between the number of trees planted since 2015 and the mean change in land value from 2015 to 2016. We can therefore reject the hypothesis that trees planted in one year will increase the value of land the following year.
Figure 6: Linear Model of Mean Land Value by Trees Planted per Neighbourhood:
The linear model above displays the correlation between mean land value and trees planted since 2015 by neighbourhood. We can see that there is infact a negative relationship between these attributes. This plot would suggest that there is a push to plant more trees in the less established neighbourhoods.
As the analysis above has shown, there is some correlation between land value and the size and number of trees by neighbourhood, however it is not enough to conclude that the existence of trees in souly responsible for the increase or decrease in the land value. To provide more conclusive evidence, this analysis should be reconducted in a few years to test the change in land value of the areas where many of the trees had been planted.